I was thinking you could use it for the actual image format (alpha) so you could change the shape of the player if you wanted to (not that i want to), but... since the way the skin engine works with % there really isnt a reason to do it. But.... just thought of a reason, for the menue button that brings up the two rows of buttons at the top and bottom you could just have an icons that reveal and the rest transparent, same for the exit buttons. But thats the only place i could see it being used.